1. Field of the Invention
This invention relates to a method and apparatus for the ultrasonic treatment of a dilute alcoholic solution in which the alcohol is vaporized from the dilute alcoholic solution.
2. Description of the Prior Art
Ultrasonic vibrations have been heretofore used to oscillate vibrators in water, with the result that cavitation is produced thereby generating steam. Alternatively, ultrasonic vibrations are utilized to be acted on liquors in order to facilitate removal of froth from beer or aging of whisky. However, ultrasonic vibrations have never been utilized for vaporization of alcohol without causing cavitation.
In the fermentation of alcohol, when a concentration of alcohol reaches a certain level, e.g. about 12%, the alcohol productivity of yeast fungii is suppressed. In recent years, alcohol-resistant fungii have been discovered but even with such fungii, the alcohol productivity is suppressed when the alcohol concentration exceeds 15%. About 10% to 20% of carbohydrates added to a fermentation mother liquor remains unfermented. Especially, when starting starchy materials are saccharified with aspergilli and are subsequently subjected to alcoholic fermentation by means of yeast fungii as with Sake, about 50% of the added starchy materials is left as sake lees in the form of dextrin, cellulose and starchy materials. This arises problems from the standpoint of saving resources and preventing ecological pollution. Moreover, it is generally accepted that for the production of alcoholic liquors having high concentrations by distillation of the liquors obtained by filtration of the fermentation liquor, about 7.5 liters of petroleum as fuel per 10 liters of the alcohol product is required. Additionally, a cooling energy which is used to cool and condense once vaporized alcohol is not negligible. It is known that production of alcohol having a high concentration requires petroleum in the same amount as the alcohol.
It is also known that for the production of aldehydes such as formaldehyde, acetoaldehyde and the like, organic and inorganic mercury compounds which involve environmental pollution problems are used.